Objectives of this program are to develop a variety of quantitative models of psychological phenomena, and to develop and apply quantitative methods useful for theoretical and empirical analysis in mental health research. Areas of concentration include (1) the study of human decision hehavior; (2) the simulation of cognitive processes, particularly of the processes of concept formation; (3) experimental investigations in psycholinguistics; (4) the development of models of psychological measurement, especially of multidimensional scaling; and (5) computational and empirical contributions to behavioral and applied statistics, notably multivariate analysis. The experimental components of the research program are greatly aided by the availability of a laboratory for computer controlled experiments.